Many types of disposable absorbent products, such as diapers, are available that have a high capacity for absorbing urine. Disposable products of this type generally comprise some sort of fluid-permeable topsheet material, an absorbent core, and a fluid-impermeable backsheet material. Although these types of absorbent structures may be highly efficient for the absorption of fluids, they cannot absorb bowel movements (i.e., hereinafter referred to as “BM”). Typically, the BM is trapped between the outer surface of the fluid-permeable topsheet and the skin of the wearer, much of it adhering to the wearer's skin.
To prevent BM from adhering to the wearer's skin, the caregiver often applies protective or “repellent” products such as vaseline or mineral oil to the buttocks and anal region before placing the absorbent article on the wearer. This procedure usually involves the caregiver's pouring of the oil or lotion, for example, in one of their hands, rubbing both hands together to distribute the substance thereon and then wiping the same on the skin of the infant. To eliminate the need for this wasteful, messy, and easily forgotten procedure, there have been numerous previous attempts to prepare absorbent articles which contain a protective or therapeutic skin care substance on the topsheet.
One substance that has been applied as a lotion to absorbent products to impart a soothing, protective coating is mineral oil. Mineral oil (also known as liquid petrolatum) is a mixture of various liquid hydrocarbons obtained by distilling the high-boiling (i.e., 300°-390° C.) fractions in petroleum. Mineral oil is liquid at ambient temperatures, e.g. 20°-25° C. As a result, mineral oil is relatively fluid and mobile, even when applied to article topsheets.
Because mineral oil is fluid and mobile at ambient temperatures, it tends not to remain localized on the surface of the topsheet, but instead migrates through the topsheet into the interior of the diaper. Accordingly, relatively high levels of mineral oil need to be applied to the topsheet to provide the desired therapeutic or protective coating lotion benefits. This leads not only to increased costs for these lotioned products, but other detrimental effects as well.
One of these detrimental effects is a decrease in the fluid handling properties as high levels of mineral oil tend to block the topsheet openings. Also, as mineral oil migrates to the interior of the article, it tends to act as a hydrophobic additive, thus decreasing the absorbency of the underlying absorbent core, if one is used. This decrease in absorbency becomes more pronounced as the level of mineral oil applied is increased.
Past attempts to solve the problems associated with BM compromised the urine handling properties of the article. Therefore, it is an object of the present invention to provide a disposable absorbent article having superior urine and BM handling properties.